Apparatus for developing diazotype material, particularly foils



Aug. 9, 1960 c. E. HERRICK, JR 2,948,208

APPARATUS FOR DEVELOPING DIAZOTYPE MATERIAL PARTICULARLY FOILS FIGZFiled July 18, 1957 4 FIG .I INVENTOR.

CLIFFORD E.HERRICP,JR.

BY W

' ATTORNEYS United States Patent APPARATUS FOR DEVELOPING DIAZOTYPEMATERIAL, PARTICULARLY FOILS Clifford E. Herrick, Jr., 'Chenango Forks,N.Y., assignor to General Aniline & Film Corporation, New York, N .Y., acorporation of Delaware Filed July 18, 1957, Ser. No. 672,596

1 Claim. (CI. 95-89) This invention relates to apparatus for developingexposed diazo sensitized material and, more particularly, to a simple,portable unit requiring no liquid developing medium.

It is well known that diazotype materials develop slowly at roomtemperature and that, for rapid development, heat and a certain amountof moisture are necessary when ammonia is used.

In developing foil instead of paper material, the moist ammonia vapormay often form a condensate on the foil causing fogging of thebackground.

In the present apparatus, the above is eliminated in that the foil ismaintained at an elevated temperature.

It is a particular object of this invention to provide for theindividual user an inexpensive, compact apparatus capable of developingexposed diazotype sheet material, especially foils, in a convenientmanner.

Other objects and advantages will become apparent from the followingdescription of the invention, pointed out in particularity in theappended claim, and taken in connection with the accompanying drawingwherein:

Fig. 1 is an elevational view in perspective of the apparatus;

Fig. 2 is a partial perspective view showing a simple grip for holdingthe material to be developed;

Fig. 3 is a top view of the apparatus shown in Fig. 1; and

Fig. 4 is a partial cross-sectional view of the flexible mounting of thegrip.

The apparatus consists essentially of a support for the material to bedeveloped in the form of a cylinder 5, open at the bottom, which ismounted by means of legs 6 onto a base plate 7. The other end of thecylinder is closed by the cover 9. A heating element 11 in the form ofan incandescent lamp is supported within the cylinder 5 in any suitablemanner, for example, by means of the plate 12 to which the socket 13 ofthe lamp is attached. The plate 12 is mounted by means of screws 14 and15 located in the cover 9 so that the lamp 11 may be raised or loweredto obtain even heat distribution on the wall of the cylinder 5.

A semi-cylindrical clip 18 is provided around the wall of the cylinderrunning parallel to the longitudinal axis thereof and held thereagainstby resilient mountings. The latter comprise two or more bolts 19 whichare firmly afiixed to the wall of the cylinder 5.

The clip 18 is provided with suitable holes so that it fits loosely overthe bolts 19, each of which retains a spring 21 which presses againstthe clip 18. A washer 22 between the spring 21 and the clip 18 assuresfirm seating of the spring 21 upon movement of the clip 18. Sufficientflexibility is provided by this mounting so that either edge of the clipmay be raised or tilted by means "ice of the handle portion 23 so as toinsert a foil or paper 24 under the clip to be held by the pressure ofthe spring 21 against the wall of the cylinder 5.

Underneath the cylinder 5 and substantially in the center thereof, isplaced a cup 26 having a conventional electrical heater element (notshown here) such as is used for a cigaret lighter.

The assembly just described is covered by another cylinder 28 of largerdiameter so that an annular space of about one half inch is maintainedbetween the inner cylinder 5 carrying the sensitized material and theinside surface of the outer cylinder 28. In order to observe the rate ofdevelopment and completion of development of the sensitized material 24,it is desirable that the outer cylinder 28 be transparent and, for thisreason, it is preferably made of glass or plastic. A plurality of vents30 are provided in the top of the cylinder 28 to permit the air toescape and be displaced by the developing gaseous medium.

In using the developing apparatus, an exposed diazo foil or paper isplaced around the cylinder 5 and under the clip 18 to be held in goodthermal contact against the wall of the cylinder. Ammonium carbonate,preferably in the form of pellets, is placed in cup 26 to be heated soas to generate the developing gas. The outer cylinder 28 is then loweredto enclose the entire assembly. The metal cylinder 5, being heated bythe radiation of the lamp 11 maintains the material to be developed atsuch a temperature that condensate may not 'form on the foil.

The gas, so generated, quickly displaces the air which may escapethrough the apertures 30 and permeates the narrow confines between thecylinder walls. Upon observing the developing of the diazo image theoperation may be stopped by shutting off the current to the heater inthe cup 26 so that no more gas is generated. The small amount of gasrequired for developing a foil or paper is insuflicient to permeate theatmosphere so that this apparatus may be used in a room without causingunpleasant odors.

I claim:

Apparatus for development of diazo sensitized material, particularlyfoils, comprising, in combination, a cylindrical support, a springbiased clip for retaining said material around said support, atransparent cylindrical cover over said support enabling the viewing ofthe progress of development and of sufficiently larger diameter to forman annular space for the developing gas, an electrically-heatedcup-shape container located axially to said cylinder and adapted to holdpellets of ammonium carbonate for generating developing gas to penneatesaid space, vents in said cover for permitting residual air to escapeand an incandescent lamp mounted inside said support for maintainingsaid support at an elevated temperature thereby preventing the formationof condensate of the developing gas upon said sensitized material.

References Cited in the file of this patent UNITED STATES PATENTS1,745,655 Allin Feb. 4, 1930 2,228,562 Dieterle Jan. 14, 1941 2,288,165Krupa et al. June 30, 1942 2,590,899 Snelling Apr. 1, 1952 FOREIGNPATENTS 478,988 Italy Mar. 7, 1953

